1998 Other Peugeot Models Diesel temp power loss, smoke, noi

This problem has been around in some degree possibly since I bought the car in 2004:

At a certain low-mid range of revs AND when under load (uphill or heavy acceleration), the engine sometimes loses power, produces a cloud of dark smoke, and - lately - makes an escaping pressure chirring noise which starts quietly and increases in volume. The problem vanishes immediately if I reduce acceleration enough.

In the past as I continued accelerating, above medium revs (after momentum was gained) the problem abruptly disappeared, the power kicked back in and the engine behaved normally again.

When accelerating slowly through the high end of the problem range of revs, the power would sometimes kick off and then on again, off and on again, at intervals of between a half second and two seconds, physically jerking the car enough to be felt as if a turbo was kicking on/off. (There is no turbo).

The extent of the loss of power has been increasing a lot over the past few weeks and especially days. The engine tends to "˜break’ into this mode very easily now, does not flick-flack anymore, and I can’t help revving the engine a little more than I need to when pulling away to help avoid a stall.

The noise is also a recent addition which at first appeared randomly a few weeks ago, then more commonly and more loudly, and now for the last few days is present every time the problem occurs.

The problem occurrs most easily in 2nd gear, but I think it used to be most in 3rd gear under load, ie uphill or heavy acceleration, especially likely on a long journey.
Lately it occurs quite easily in 1st.
It’s quite difficult to make it happen in 4th.

The smoke smells acrid, at least sometimes. I’m not sure if it is always the same colour - it may depend on the light and angle, I’m not experienced enough to tell. Sometimes it appears blue-ish especially going uphill but normally under heavy acceleration it appears the more usual black or dark grey. (My wife feels that in the first years after purchase it was more often white, although I wonder if this was just because it was at night at those times and the grey appeared whiter in the dark!)

The car has had major and minor services and has had a timing belt change years ago, but these did not affect the problem except that the smoke usually improved for 3-6 months after a service. Fewer months lately. My regular and reliable mechanic was surpised by the dirt in the filter two months after another garage serviced the car last year. However even after the next service with him, the smoke returned very quickly again as well.

Last year I added a cleaning agent to the fuel before a long journey, which improved the smoke problem for some time. The power flick-flack has always been occurring, though I suspect it might have been less common when the car was running clean.

I’ve never noticed anything unusual on the guages, except once years back when there was a brake fluid leak.

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Wednesday, July 16th, 2008 AT 7:18 AM

1 Reply

DAVE H

EXPERT

13,535 POSTS

Have your mechanic check/clean or replace the TPS (throttle position sensor).